The PI proposes to develop and test a novel method for studying the contribution of auditory feedback from an individual's own vocalizations to vocal production and to vocal learning. This work will be done in a songbird, the zebra finch, because the songbird vocal system provides the most accessible animal model for studying some of the basic mechanisms of human speech. Young songbirds learn their vocalizations from external tutors through a process of imitation that resembles human speech acquisition. Vocal imitation depends on auditory information not only to hear the vocalizations that are copied, but also to process the individual's own vocalizations so that they are shaped to match the tutor's. Vocal production and sensory processing of vocal signals depend on specialized structures that have been identified in the songbird foreb1ain. To date, methods for studying the role of audition in songbird vocal learning have been either crude, e.g. surgical deafening, or partial, e.g. episodic delayed feedback delivered through speakers. A more precise method of delivering auditory information would permit the role of real-time auditory feedback in song learning and maintenance to be quantitatively assessed. The PI proposes 1) to develop a novel headphone-microphone device, worn by the bird, that will enable auditory feedback during vocalization to be controlled and manipulated, 2) to present altered auditory feedback during vocal production in adults and assess song stability, and 3) to present altered auditory feedback in juveniles during vocal practice and assess effects on song production and learning. These studies will produce an initial body of data that will drive significant future research at both the behavioral and neural levels. The eventual results will advance our understanding of fundamental mechanisms of vocal learning in songbirds.